1. Field of Invention
This invention relates generally to a track and slide assembly for a sailboat, the track being attached to the mast of the boat and the slides which ride along the track being coupled to the luff of a sail whose base is hitched to a boom, whereby the sail may be raised on the mast or lowered, and more particularly to an assembly of the type in which the slides are rotatable on the track as well as slidable therealong, and therefore do not bind to the track when a torque is applied to the slides by the sail.
2. Status of Prior Art
In a typical modern sailboat having fore and aft sails, the sailboat is provided with a mainsail, a foresail and a jib, the mainsail being supported by a mast. The mainsail, which is triangular, is hitched at its base to a boom which can swing about the lower part of the mast in either direction in relation to the longitudinal axis of the boat.
In order to make it possible to control, reef and stow the mainsail, use is made of a track and slide assembly whose track is attached to the mast and whose slides which ride along the track are coupled at spaced positions to the vertical or luff side of the triangular sail. In this way, when the sail is raised by a halyard to its full height on the mast, the slides then ride up the track, and when the sail is lowered so that it can be furled on the boom, the slides then ride down the track. When the sail is to be reefed to reduce the area exposed to wind, as by folding a portion of its foot and securing it to the boom with reef points, the slides then ride down the track to the extent necessary to effect reefing.
A mainsail exposed to wind forces will often subject the slides coupled to the luff of the sail to torque and other forces which may impair the ability of the slides to ride along the track. And depending on the design of the track and slide assembly, these forces may act to decouple the slides from the track and render the sail ineffective.
In many conventional track and slide assemblies, the slides are rectangular in shape or in the form of rectangular cars that run along the track. Should a torque force be applied to these slides by a mainsail, the slides, which are incapable of turning with respect to the track, will then bind to the track, thereby preventing sliding movement and making it impossible to control the mainsail.
And in those designs in which the slides ride along lips projecting from opposite sides of the track, a strong pulling force exerted on the slides by the mainsail may act to compress and deflect these lips and decouple the slides from the track.
An important factor which comes into play in the effectiveness of a track and slide assembly is the ability of the slides to ride freely up and down the track so that the sail can be raised or lowered without difficulty. Such movement is resisted should the slides encounter significant friction. It is for this reason that in some instances tracks are made of TEFLON (PTFE), a synthetic plastic material having an exceptionally low coefficient of friction. But the structural strength of a TEFLON track is not great, and the track may not stand up when heavy forces are exerted thereon by the slides coupled to the sail.
Another factor that must be taken into account in considering the effectiveness of a track and slide assembly is the manner in which the slides are linked to the luff of the mainsail. If the slides are rigidly coupled to battens attached to the luff of the sail, and in response to a wind force the sail assumes an acute angle with respect to the track mounted on the mast, then if the link between the slides and the mainsail is inflexible, this action may either disrupt the link or detach the slides from the track.
Of prior art interest are the patents to Benedict, U.S. Pat. No. 3,092,064 and Rand, U.S. Pat. No. 259,209.